Conducting a scientific literature review is a time consuming activity. This holds for both finding and comparing the related literature. In this paper, we present a workflow and system designed to, among other things, compare research contributions in a scientific knowledge graph. In order to compare contributions, multiple tasks are performed, including finding similar contributions, mapping properties and visualizing the comparison. The presented workflow is implemented in the Open Research Knowledge Graph (ORKG) which enables researchers to find and compare related literature. A preliminary evaluation has been conducted with researchers. Results show that researchers are satisfied with the usability of the user interface, but more importantly, they acknowledge the need and usefulness of contribution comparisons.